Re: Scripts vs APIs

Virtual Reality (
Thu, 8 Sep 94 12:38:43 BST

I've not being fully following this Scripts vs API discussion but what
Dave Raggett said caught my eye.

>I still believe that VRML should be primarily a scene description language
>that sticks to describing the object classes and instances making up a
>scene as "data" and does not evolve into yet another scripting language.
>- Mark Pesce's implementation fits firmly into this model.

I agree with this view of VRML. However, to describe complex virtual worlds
a scripting language may be required. For example, if I want to model a
dynamic system, such as a flock of birds, I want to be able to "program"
the path each bird will take. May be to change it slightly and see what
happens if they crash into each other. Some form of animation/scripting
language is required for this. I can't think of another way of doing it
without the use of a C API, and I don't want to use a C API.

>For VRML to work, though, given the limited bandwidth of the net, we
>need a way to avoid having to send huge geometry files. It is essential
>to be able to use scripts to generate scenes locally at the client from
>higher level descriptions sent as part of VRML. This is straightforward
>to achieve if we use URLs to associate scripts with VRML documents.

I like this idea. RenderWare scripts include high level object building
functions such as block, cone etc. These build the appropriate shape at
load time.

How do I go about programming URLs?

>I am also very keen to open the flood gates to "ordinary folks" to
>create their own rich VR scenes and applications. I want to be able to
>use someone else's fractal cloud generator and to combine it with trees
>from here and buildings from there. For this to happen we need to keep
>VRML simple; to combine it with simple scripting languages; and to allow
>the use of geometry data created with commonplace 3D modelling tools.

This is just file conversion. I see no reason why a filter couldn't be
written to take a fractal tree out of Vista Pro and be converted into
a VRML file (apart from the effort it's going to require to figure out
DEM, DXF and 3DS file formats).

>To encourage the rapid deployment of VRML, we need a libvrml which handles
>parsing and provides for integration with OpenGL, PEX and Renderware etc.
>I want the library to include a simple scripting language too, to act as
>an existance proof of how VRML can support intensional object classes.
>It should also support the most common 3D modelling formats such as DXF.

I agree here again, but the problem is a library can't be written until
the syntax is sorted out. I'd like to use VRML with RenderWare on a PC and
I'm dieing to get started with this. Can someone provide the syntax for

How much of this has already been written? If there's a parser all ready
I don't want to re-write it. Likewise with the scripting language.

>We need to start figuring out ways in which the challenge of building this
>library can be shared out across the net. Lets go for it!

Great idea.


Peter Johnson


Virtual World Design Project
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"If you give an infinite number of monkeys an infinite number of graphic design
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